fix(db): 2817 - Add shutdown blocker for metadata store
fix(db): 2817 - Add shutdown blocker for metadata store

mozilla/activity-stream,AdamHillier/activity-stream,sarracini/activity-stream,Mardak/activity-stream,mozilla/activity-stream,rlr/activity-streams,sarracini/activity-stream,Mardak/activity-stream,Mardak/activity-stream,JaredKerim-Mozilla/activity-stream,rlr/activity-streams,Mardak/activity-stream,rlr/activity-streams,JaredKerim-Mozilla/activity-stream,AdamHillier/activity-stream,mozilla/activity-streams,sarracini/activity-stream,mozilla/activity-streams,AdamHillier/activity-stream,sarracini/activity-stream,mozilla/activity-stream,rlr/activity-streams,mozilla/activity-stream,JaredKerim-Mozilla/activity-stream,JaredKerim-Mozilla/activity-stream,AdamHillier/activity-stream